#include<stdio.h>
#include<math.h>
#include<stdlib.h>
int a[8];
char *day[]={"","MO","TU","WE","TH","FR","SA","SU"};
main()
{
    int i,t,j;
    a[4]=6;
    for(i=1;i<=3;i++)
    {
        a[i]=2;
        if(!a[i+3])a[i+3]=7;
        else{
             a[i]=0;
             continue;
        }
        for(t=1;t<=3;t++)
        {
            if(!a[t]) a[t]=5;
            else continue;
            if(!a[t+2]) a[t+2]=4;
            else {
                a[t]=0;
                continue;
            }
            for(j=5;j<7;j++)
            {
                if(!a[j])a[j]=3;
                else continue;
                if(!a[j+1])a[j+1]=1;
                else{  a[j]=0; continue;}
                for(i=1;i<=7;i++)
                printf("Doctor %c is on duty %s.\n",'A'+a[i]-1,day[i]);
                exit(0);
            }
        }
    }
}